(CNN) -- Syrian rebels have taken control of the only crossing between Syria and the Israeli-occupied Golan Heights, the Syrian Observatory for Human Rights said.

Rebels attacked government checkpoints and battled Syrian forces in the largely abandoned city of Quneitra before gaining control of the city's border crossing, the opposition group said.

A steady stream of gunfire could be seen in Quneitra from the Israeli-occupied side. Rebels opened fire on the Syrian forces, who responded with tank fire to try to force the rebels back.

Mortars and small arms fire caused the bushes and shrubs to catch on fire.

The Israeli military has not publicly commented on the report that rebels have taken over the crossing.

But spokesman Peter Lerner said mortar shells fell on the Israeli side of the border near the Quneitra crossing. He said Israel is aware of fighting between Syrian forces and rebels in Quneitra and is taking necessary precautions to prevent spillover.

Lerner said Israeli authorities have instructed farmers in the Golan Heights not to approach the border fence in the Quneitra area due to the ongoing fighting on the Syrian side.